When managing a network gateway through an IP network, the network gateway needs an IP address for communication. The IP address of the network gateway allows IP data packets be routed to the network gateway and allows the network gateway to transmit IP data packets.
However, in certain network environment, there are not enough IP addresses. As a result, there may not be any additional IP addresses available for the use of the network gateway. In such case, the network gateway may still be able to route and/or switch IP data packets, but it cannot transmit its own IP data packets or receive IP data packets destined to the network gateway.
FIG. 1 is a typical network environment where router 111 connects to firewall 150 via network interface 113 to connect to inter-connected networks 101 via network interface 112. Inter-connected networks 101 may be the Internet or another network. Firewall 150 connects to router 111 via network interface 151, connects to host 161 via network interface 152 and connects to network node 164 via network interface 153. IP enabled devices are connected to firewall 150, such as host 161 via network interface 162 and network node 164 via network interface 163. Each of network interfaces 112, 113, 151, 152, 153, 162 and 163 is assigned with one IP address. Therefore there are seven IP addresses needed. The internet service provider (ISP) may then assign seven IP addresses for router 111 to use. Host 161 and network node 164 are nodes which are capable of sending, receiving, or forwarding Internet Protocol (IP) data packets.
In FIG. 2, when network gateway 170 is added between router 111 and firewall 150, the problem is that there is no further IP address available to assign to network interfaces 171 and 172 of network gateway 170.
From discussion above, it should be apparent that there is a need for a network gateway to communicate with other nodes in an IP network in which the network gateway is not assigned with an IP address.